Struktur von α‐(Dimethylamino)benzyllithium in Lösung: Dynamisches Gleichgewicht zwischen einer η¹‐ und einer η³‐Spezies

Abstract

Structure of α‐(Dimethylamino)benzyllithium in Solution: Dynamic Equilibrium between an η 1 and an η 3 Species Temperature‐dependent 1 H‐ and 13 C‐NMR‐spektroscopic shifts observed in tetrahydrofuran are indicative of an equilibrium between a high‐temperature η 3 and a low‐temperature η 1 species. MNDO calculations are in accord with this view, and HOESY experiments proof it, too. The equilibrium is controled by solvation or complexation, low Lewis basicity of the solvent or bidentate ligands favoring the η 3 , high Lewis basicity or tridentate ligands the η 1 species. Equilibrium as well as rate constants have been estimated, and from their temperature dependence the thermodynamics of the equilibrium and the activation barriers were calculated.